The processing capacities of communication devices such as Layer 2 switches and routers have improved with an increase in demand for communication. On the other hand, power consumption has increased. Therefore, it is desirable to reduce the power consumption of communication devices.
As for the reduction of the power consumption of communication devices, a technique for changing a clock frequency in response to a packet flow rate is known. In addition, a technique for stopping the supply of power to an inactive port is known.
In addition, a technique where a client requests a server to reduce the transfer rate of data and the client enters a power saving mode after the reduction of the transfer rate is known. In addition, a technique for reducing power consumption by changing the speed of communication between devices is known. Japanese Laid-open Patent Publication No. 2007-228491, Japanese Laid-open Patent Publication No. 11-88458, Japanese Laid-open Patent Publication No. 2009-237933, and Japanese Laid-open Patent Publication No. 2006-293983 discuss such techniques.